James gave me access to post just about a year ago, so I figured I might as well use that access.
When I first started learning about the science behind nutrition and exercise, I learned that everything I knew was wrong. After that, I learned that everything I had just learned was wrong. I kept repeating this process until I figured out that applying studies of nutrition and general health to a country’s population doesn’t work the way I want a ‘hard’ science to work. Sure, physiology, kinesiology, and endocrinology are all pretty well understood. But, try applying them all at the same time to three hundred million people, and there are going to be some problems. Why?
Correlation is not causation. Most people don’t stop to think about this, and their ignorance affects the way health recommendations are made and followed. Some time ago, someone astutely noticed that people who got checkups from their doctors at least once per year tended to be healthier than those who did not. People assumed the relationship was causative and now we all know that we need to have yearly checkups. It turns out, the type of people who took it upon themselves to get annual physicals were also the type of people who valued taking care of their bodies. Since I am not even close to being a doctor, I am not even going to think about telling anyone what to do with regards to doctors. I will, however, link to this Time Magazine article from 2004, which explains how some Federal guidelines on preventative medicine might not be what you think they are.
Again and again, observational studies have tried to figure out just what exactly healthy people are doing that makes them healthy. Again and again, people take these studies and apply any findings in ways that only slightly differ from a reductio ad absurdum: Did a study show any kind of link between fat intake and heart disease? Better eat nothing but carbs! Excessive carb intake linked to diabetes and high triglycerides? Fresh fruit must be poison, and I certainly don’t need vegetables! Link found between serum cholesterol and cardiovascular disease? Those deviled eggs are truly from the devil!
The problem is, health recommendations made by respected sources can easily become self-fulfilling prophecies. If the population of ‘fitness people’ learned that water consumed below 40 degrees F caused cancer, and those people all took this advice, that fact (which I feel I ought to stress that I just made up) would wind up being true.
This club of overreaction to observational studies recently got a new member. It turns out salt is not nearly the villain it has been made out to be. Scientific American – It’s Time to End the War on Salt. Basically, the effects of salt consumption on blood pressure are minimal for the vast majority of people. Of course, researchers don’t just spout claims for their own entertainment, sodium intake recommendations to have legitimate motivations:
Some physicians argue that although tiny blood pressure drops will not have a big effect on individuals—they will not really affect your risk of having a heart attack—they may end up saving lives at the population level, in part because a small percentage of the population, including some African-Americans and elderly individuals, seem to be hypersensitive to salt.
So, is there a solution to this nonstop parade of confusion? There is sure no perfect solution, but here’s what seems to work for me:
- Pay attention to what I eat (It seems any nutritional protocol works if it is actually followed)
- Read up and stay informed
- Eat vegetables
- Avoid broscience using lots and lots of skepticism (and yes, this applies to the writings of paunchy bloggers)
Before I close, I should point out what is most likely the most hotly contested observational health study of the 20th century: Ancel Keys’ Seven Countries Study. I am not going to offer any commentary on it because I think James would have more fun with that one.